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THE EFFECTS OF EARLY FOCAL BRAIN
INJURY ON LANGUAGE AND COGNITION:
Plasticity and Development
Adult
Brodmann,1909
Key Issue:
Link between
Behaviors
their Neural Substrate
(i.e., language production
Broca’s area)
How do associations between
behaviors and the brain structures (that
control them) emerge?
Laterality
How do Cognitive skills become lateralized?
(i.e., Language
Left Hemisphere)
Early in life cognitive functions are bilateral
(Infants and young children use different neural
networks for language compared to adults)
Change across development:
PLASTICITY
Plasticity refers to the capacity for change
Term widely used within neurosciences, refers to changes at
all levels of the cognitive-neural system from neurochemistry
to behavior.
Plasticity is fundamental
for brain development
1. Brain development is DYNAMIC
-Continuously changing
(i.e., new synaptic connections, new memory…)
2. Change requires INTERACTION
-Intrinsic factors (Nature: gene expression)
-Extrinsic factors (Nurture: environment, experience,
learning)
Complexity of Nature X Nurture Interaction
Difficult to link changes in complex behaviors to the
corresponding neural changes
- Animal models: i.e., sensory deprivation studies,
neural pathway alteration studies
- Studies on Human Patient Populations:
i.e., Congenital Deaf, Stroke Patients…
Children with Perinatal Focal Brain Injury
1. Single, unilateral focal lesion (mostly from strokes)
2. Normal or corrected to normal vision / audition.
3. IQ within normal range
From Moses, 1999
HOW DOES VERY EARLY FOCAL
BRAIN INJURY AFFECT
LANGUAGE ACQUISITION?
PRIMARY LANGUAGE AREAS IN ADULTS ARE
IN THE LEFT HEMISPHERE
LEFT HEMISPHERE
RIGHT HEMISPHERE
BROCA’S AREA:
PRODUCTION OF LANGUAGE
LEFT HEMISPHERE
WERNIKE’S AREA:
COMPREHENSION OF LANGUAGE
LEFT HEMISPHERE – ADULT
Vocabulary Production in
Children with Early Injury
PRODUCTION
COMPREHENSION
LEFT HEMISPHERE
LEFT POSTERIOR TEMPORAL
LESIONS
VOCABULARY PRODUCTION
DEFICITS.
LPT LESION
LEFT HEMISPHERE – ADULT
Vocabulary Comprehension
in Children with Early Injury
PRODUCTION
COMPREHENSION
LEFT HEMISPHERE
RIGHT HEMISPHERE
LPT LESION
LEFT POSTERIOR TEMPORAL LESIONS
NO COMPREHENSION DEFICITS
RIGHT HEMISPHERE LESIONS
+ COMPREHENSION DEFICITS
Typical Developmental changes in
Language Processing: an ERPs study
Children at 13- and 20-months were tested on a “known”
and “unknown” word comprehension task (ERPs recorded)
 At 13 mo.: Brain activation patterns were bilateral and
extended from frontal through posterior temporal and
parietal regions.
 By 20 mo.: Brain activation patterns were left lateralized
over traditional language areas.
Neville et al., 1991
Language Acquisition neural networks
extend bilaterally from frontal to posterior areas
whereas
With learning and experience, Language networks
become Left Lateralized and localized areas more
efficient for language processing
Narrative Production in
School-age Children with Early Injury
By age 7, mastered basic semantic and
grammatical features of language.
 within the normal range on all measures of
lexical (age 5) and morphosyntactic development
However,
they used complex syntax and narrative structures
less frequently than typical children, even by 12yr
 subtle deficits
Summary: Language in Children
with Early Brain Lesions
1. All children were delayed in some aspect of
language regardless of the lesion side.
2. Opposite profile from adult lesion populations
 RIGHT HEMISPHERE INJURY IS ASSOCIATED
WITH DEFICITS IN WORD COMPREHENSION.
 LEFT POSTERIOR TEMPORAL INJURY IS
ASSOCIATED WITH DEFICITS IN WORD AND
GRAMMATICAL PRODUCTION.
Summary: Language in Children
with Early Brain Lesions
3. Subtle deficits persistent over time
 BY AGE 5, CHILDREN APPEAR TO “CATCHUP.” THEY SCORE WITHIN THE NORMAL RANGE
ON MEASURES OF SEMANTICS AND
GRAMMATICAL MORPHOLOGY.
 NO SITE SPECIFIC EFFECTS OBSERVED
AFTER AGE 7 (AGE 5 FOR LEXICAL DEFICITS).
Summary: Language in Children
with Early Brain Lesions
HOWEVER,
ALTHOUGH THEY SCORE WITHIN THE NORMAL
RANGE, THEY TEND TO USE LESS COMPLICATED
LANGUAGE FORMS
4. BILATERALLY DISTRIBUTED LANGUAGE NETWORKS in
Typical Developing Infants can in part explain the nature
of recovery/development in this population
Spatial Cognitive Development in
Children with
Early Focal Brain Injury
SPATIAL ANALYSIS
The ability to specify both the parts and the overall
configuration of a visually presented pattern, and to
understand how the parts are related to form a
whole.
Spatial analysis thus involves the ability:

to segment a pattern into a set of constituent
parts
 to integrate those parts into a coherent whole
Visual Pattern
Processing
Segmentation of
the parts
Front
Integration of parts
into a whole
Back
LEFT HEMISPHERE
Front
Back
RIGHT HEMISPHERE
MEMORY REPRODUCTION:
ADULT LESION PATIENTS
PATTERNS OF SPATIAL DEFICIT IN ADULTS
WITH RIGHT AND LEFT POSTERIOR BRAIN
INJURY
 LEFT POSTERIOR BRAIN INJURY: Impairs ability to define
and encode the parts of a spatial array.
• Oversimplification of spatial patterns
• Omission of pattern detail
• rely on overall configural cues and ignore specific
elements of spatial patterns.
 RIGHT POSTERIOR BRAIN INJURY: Impairs ability to
integrate pattern elements into a coherent whole.
• Focus on the parts or elements of the pattern
• Able to produce or report the parts of a form but fail to
attend to the overall configuration.
FUNCTIONAL
MAGNETIC RESONANCE IMAGING
(FMRI) OF TYPICAL ADULTS
Part-Whole Stimulus
S
S
S
S
S
S
S S S SS
S
S
S
S
S
S
Two tasks:
1. Attend to the WHOLE.
2. Attend to the PARTS.
Adult Brain Activation on the
Part-Whole Processing Task
Attend to the Whole:
Right > Left
RIGHT
LEFT
Attend to the Part:
Left > Right
Back
Front
VISUOSPATIAL PROCESSING IN
CHILDREN WITH
EARLY BRAIN INJURY
MODEL HIERARCHICAL FORMS FOR THE
MEMORY REPRODUCTION TASK
Examples from 5-year-olds
(5yrs, 4mo)
(5yrs, 7mo)
(5yrs, 8mo)
(5yrs, 8mo)
Longitudinal examples from normal controls
MODEL
(6yrs, 10mo)
(6yrs, 3mo)
(6yrs, 5mo)
MODEL
(7yrs, 10mo)
(9yrs, 0mo)
(9yrs, 3mo)
3 Children with LEFT Hemisphere Stroke: LOCAL Processing Deficit
Model
(5yr, 1mo)
(5yr, 1mo)
(6yr, 0mo)
3 Children with RIGHT Hemisphere Stroke: GLOBAL Processing Deficit
Model
(6yr, 2mo)
(6yr, 3mo)
(6yr, 11mo)
Mean Accuracy (0-5)
REPRODUCTION ACCURACY
(5-7year olds and 9-12 year olds)
3.5
3
Global
Local
2.5
2
RPL
LPL
Controls
Control group performs equally well on global and local
RH – deficit global;
LH – deficit local
HOUSE DRAWINGS OF TYPICALLY
DEVELOPING 3.5- TO 5-YEAR OLDS
HOUSE DRAWING OF CHILDREN WITH
RIGHT OR LEFT FOCAL BRAIN INJURY
4 Children with LH Lesion: LOCAL Processing Deficit
4 Children with RH Lesion: GLOBAL Processing Deficit
LEFT
hemisphere
brain injury
RIGHT
hemisphere
brain injury
Attend to the Whole:
Right > Left
RIGHT
LEFT
Attend to the Part:
Left > Right
SPATIAL ANALYSIS IN CHILDREN
WITH EARLY FOCAL BRAIN INJURY
1. DEFICITS ARE MILDER THAN THOSE
OBSERVED AMONG ADULTS WITH
COMPARABLE INJURY.
2. THE PATTERNS OF DEFICIT ASSOCIATED
WITH LEFT OR RIGHT POSTERIOR INJURY
ARE SIMILAR IN ADULTS AND CHILDREN.
SPATIAL ANALYSIS IN CHILDREN WITH EARLY
FOCAL BRAIN INJURY
3. DEFICITS ARE PERSISTENT BUT MILD AND OFTEN NOT
EVIDENT ON THE SAME MEASURES OVER TIME.
DEFICITS ARE MOST EVIDENT ON TASKS THAT ARE
CHALLENGING FOR NORMALLY DEVELOPING PEERS. FOR
MOST TASK, CHILDREN EVENTUALLY ACHIEVE CEILING
LEVELS OF PERFORMANCE - AT LEAST FOR MEASURES
OF PRODUCT.
4. SOME EVIDENCE FOR DEVELOPMENT OF
COMPENSATORY STRATEGIES.
NEW TECHNIQUES FOR ASKING QUESTIONS ABOUT
PATTERNS OF NEURAL ORGANIZATION: FUNCTIONAL
IMAGING.
Conclusions
 Brain development is a dynamic, adaptive process.
 The capacity for brain adaptation is evident from the
earliest point in development.
 Studies of children with focal brain injury illustrate the
plasticity of the developing brain, that is the ability to
organize differently, to adapt.
 But these same studies also point to limits on plasticity.
… Question?
Nature v Nurture
NATURE

Most of the information necessary to build a human
brain is latent within the genes.

Development consists of a process of a
maturationally–defined unfolding or triggering of the
information contained within the genes.

Deviation from that essential plan is an anomaly
requiring exceptional developmental mechanisms.
...Nature vs. Nurture
NURTURE

Most of the information that shapes the human mind
comes from the structure of the external world.

Some experiences are common experience while
others are unique to the individual.

Development is a process of progressive
differentiation of functionally equipotential cortical
tissue.
An Alternative View

BOTH Nature and Nurture matter.

Neither is a sufficient account of the
development of brain-behavior relations.

They influence one another -- i.e. they
INTERACT.
An example of Nature X Nurture Interaction
Activity Dependent Competition and Cell Death
Intrinsic cue  Nerve Growth Factor (NGF)
Extrinsic cue  Sensory stimulation (i.e.,
Neuronal Activity
)
Cells compete for NGF, the ones that activate first and most
for
make connections and get NGF, the others die.